(CNN) -- A sixth person in the United States has died from lung disease related to vaping, Kansas health officials said Tuesday. The woman was older than 50 and had a history of health problems. She became seriously ill shortly after she started using e-cigarettes and her symptoms progressed rapidly. It's not clear what type of vaping products she used, the Kansas Department of Health and Environment said.
The death marks the first in the state, but raises even more concern about the safety and regulation of e-cigarettes.
The US Centers for Disease Control and Prevention, the Food and Drug Administration and state health departments have been investigating this outbreak. Health officials say they haven't found a definitive cause or a clear connection between cases, but some are zeroing in on potential clues.
Here is what you need to know about vaping and vaping-related illnesses in the United States.
How many people have gotten sick and who has died?
As of Friday, there have been more than 450 possible cases of lung illness associated with using e-cigarettes reported to the CDC across 33 states and the US Virgin Islands. The numbers have been changing frequently.
Before the death in Kansas, five deaths were reported in California, Illinois, Indiana, Minnesota and Oregon.
Kansas health officials reported the patient who died was older than 50, had a history of underlying health issues and "was hospitalized with symptoms that progressed rapidly," according to a statement from the Kansas Department of Health and Environment.
Health officials said it wasn't clear what type of vaping products the patient was using.
The first death from lung illness linked to vaping in the United States was reported in Illinois in August. The person who died was an adult. Oregon saw the second death in the nationwide outbreak, then Minnesota and Indiana. The fifth death, reported Friday, was in California.
What have vaping illness investigations found so far?
The federal investigation into the link between vaping and severe lung illnesses is ongoing and has not identified a cause, but all reported cases have indicated the use of e-cigarette products and some patients have reported using e-cigarettes containing cannabinoid products, such as THC.
There are also separate investigations being conducted in separate states.
New York health officials said last week that extremely high levels of the chemical vitamin E acetate were found in nearly all cannabis-containing vaping products that were analyzed as part of the investigation. At least one vape product containing this chemical has been linked to each person who fell ill and submitted a product for testing in the state.
Laboratory tests conducted at the New York State Department of Health's Wadsworth Center in Albany showed "very high levels" of vitamin E acetate in the cannabis-containing samples, the state health department announced.
Vitamin E acetate is now "a key focus" of the state's investigation into the illnesses, the New York Department of Health said. Some of the products that have been found to contain vitamin E acetate are candy-flavored vapes.
New York Gov. Andrew Cuomo on Monday ordered the state health department to issue subpoenas to three companies that market thickening agents to companies that manufacture vape liquids -- and more companies are expected to be investigated.
The Wadsworth Center obtained samples of thickeners from those three companies and determined "they are nearly pure vitamin E acetate oil," according to the governor's office.
What do doctors say?
The CDC says e-cigarettes should never be used by youth, young adults, pregnant women or adults who do not currently use tobacco products.
While an investigation into the lung illness outbreak is ongoing, people should consider not using e-cigarette products and people who do should monitor themselves for symptoms, the CDC said Friday.
"It is time to stop vaping," Dr. Lee Norman, secretary of the Kansas Department of Health and Environment and the state health officer, said in the statement Tuesday announcing the country's sixth death.
"If you or a loved one is vaping, please stop. The recent deaths across our country, combined with hundreds of reported lung injury cases continue to intensify. I'm extremely alarmed for the health and safety of Kansans who are using vaping products and urge them to stop until we can determine the cause of vaping related lung injuries and death," Norman said.
Tuesday, the American Lung Association warned that "e-cigarettes are not safe" and can cause irreversible lung damage and disease.
"No one should use e-cigarettes or any other tobacco product. This message is even more urgent today following the increasing reports of vaping-related illnesses and deaths nationwide," Harold Wimmer, national president and CEO of the association, said in a written statement.
The American Medical Association recently urged the public to avoid the use of e-cigarette products until health officials further investigate and understand the cause of the outbreak.
"The AMA recommends anyone who has recently used e-cigarette products to seek medical care promptly if they experience any adverse health effects, particularly coughing, shortness of breath or chest pain," Dr. Patrice Harris, the association's president, said in a written statement Monday.
Harris also had a message for the FDA.
"We must not stand by while e-cigarettes continue to go unregulated. We urge the US Food and Drug Administration (FDA) to speed up the regulation of e-cigarettes and remove all unregulated products from the market," she said in part. "We also call on the FDA to immediately ban flavors, as well as marketing practices, that enhance the appeal of e-cigarette products to youth."
What is the US Food and Drug Administration doing?
FDA spokeswoman Stephanie Caccomo said in an emailed statement Tuesday that getting to the bottom of the illnesses linked with vaping remains a "top priority" for the agency and its partners.
"At this time, more information is needed to better understand whether there's a relationship between any specific products or substances and the reported illnesses. The illnesses under investigation involve the broader use of vaping products -- including those being used with substances like THC; e-cigarettes are considered one type of vaping product," the statement said in part.
The FDA is also taking action to stop the youth vaping epidemic, the statement said.
"To combat the epidemic rise in youth use of e-cigarettes, we're aggressively enforcing the law and investing in campaigns to educate youth about the dangers of e-cigarette use. Our educational efforts include youth-focused prevention messages on TV, digital platforms, posters in high school bathrooms, and lesson plans developed with Scholastic for educators," the statement said.
"We'll continue using all of our tools to protect kids, including enforcement actions and penalties. We have consistently said that if the disturbing rise in youth e-cigarette use continues, especially through the use of flavors that appeal to kids, we'll take even more aggressive action. We will do what's necessary to end the youth e-cigarette epidemic."
In a move to crack down on e-cigarette use among youth, the FDA on Monday issued a warning letter to leading e-cigarette maker Juul for marketing its product as a safer alternative to cigarettes.
The FDA states in the warning letter that Juul has marketed its products as "modified risk tobacco products" without an appropriate FDA order in effect. The products have been referred to as "99% safer" than cigarettes or "totally safe" -- and such statements were made to children in school, according to the letter.
The FDA ordered Juul to respond within 15 working days with corrective actions and its plan to comply with federal law. The letter noted that failure to comply could result in fines, seizures or injunction.
Juul has maintained that its products are intended to convert adult smokers to what it described in the past as a less-harmful alternative. In other communications, the company says it cannot make claims its products are safer, in line with FDA regulations.
"We are reviewing the letters and will fully cooperate," according to Ted Kwong, a Juul Labs spokesperson.
The warning letter is the latest development in the FDA's ongoing investigation related to Juul, according to the agency. A two-day congressional hearing was held in July to probe the company's role in the youth vaping epidemic.
"Regardless of where products like e-cigarettes fall on the continuum of tobacco product risk, the law is clear that, before marketing tobacco products for reduced risk, companies must demonstrate with scientific evidence that their specific product does in fact pose less risk or is less harmful. JUUL has ignored the law, and very concerningly, has made some of these statements in school to our nation's youth," Dr. Ned Sharpless, acting FDA commissioner, said in the agency's news release Monday.
"We will continue to scrutinize tobacco product marketing and take action as appropriate to ensure that the public is not misled into believing a certain product has been proven less risky or less harmful," he said. "We've also put the industry on notice: If the disturbing rise in youth e-cigarette use continues, especially through the use of flavors that appeal to kids, we'll take even more aggressive action."
Some public figures and lawmakers have argued that the FDA could do more.
US Senate Democratic Whip Dick Durbin has criticized the FDA and called on the agency to do more to regulate e-cigarettes.
Friday, after the news of additional deaths tied to vaping spread, Durbin called on Sharpless to move to regulate e-cigarettes and flavors in the next 10 days. Durbin said he would call for Sharpless' resignation if he did not take action.
Then on Monday, Durbin said again in a news conference that it's time Sharpless "either does something or resigns." He added that public education on the issue is not enough and enforcement is needed.
"We have to send people undercover into these places that are selling these devices, and when we nail them selling them to people underage, they pay a heavy price for it. The word gets out quickly in the retail community," he said.
In response the FDA has said that it looks forward to "engaging with Senator Durbin, along with all members of Congress" on this issue.
Is there action to ban e-cigarette products?
New York's Cuomo wants to ban flavored e-cigarettes and said in a statement Monday that he will advance new legislation to do so.
Tuesday, Bloomberg Philanthropies, the foundation run by former New York Mayor Michael Bloomberg, announced the launch of a new $160 million initiative to curb e-cigarette use among young people in the United States.
The goals of the three-year program include banning all flavored e-cigarettes, and stopping Juul and other e-cigarette companies from marketing their products to children, the organization said in a news release. It will be led by the Campaign for Tobacco-Free Kids, which will partner with other leading organizations including parent and community groups concerned about the nation's children and health.
The launch comes on the same day Bloomberg and Matt Myers, of the Campaign for Tobacco-Free Kids, penned an opinion piece in The New York Times. They wrote that "banning flavored e-cigarettes is the most important thing we can do to reduce use among young people" and took aim at the FDA for not doing so.
"The FDA can ban flavors immediately, but it has repeatedly kicked the can down the road when it comes to taking serious steps," Bloomberg and Myers wrote.
Last week, Michigan Gov. Gretchen Whitmer announced that the state is set to become the first to ban the sale of flavored e-cigarettes. The ban gives sellers 30 days to comply and lasts six months -- though the governor can decide to renew it. This includes sales in brick-and-mortar stores and online.
In July, San Francisco Mayor London Breed signed an ordinance that effectively banned e-cigarette sales in the city -- the first of its kind in the United States.
While it's not a ban, in March, the FDA proposed policy to prevent youth access to e-cigarettes and other flavored tobacco products.
The draft compliance policy would take action against stores selling flavored e-cigarette products that are accessible to minors and against websites selling them without verifying buyers' ages and limiting the maximum quantities they sell. This proposal was made under former FDA Commissioner Dr. Scott Gottlieb.
"We will have more details to share about the final compliance policy soon, including our plans to address this alarming trend among youth," the agency said in its statement to CNN on Tuesday.